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Finding the Fourth Proportional to 87.42, 130.45 and 78.71

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Solution

The fourth proportional to 87.42, 130.45 and 78.71 is: 117.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.42 : 130.45 = 78.71 : x
  2. Step 2: Convert to fraction form
    87.42/130.45 = 78.71/x
  3. Step 3: Cross multiply
    87.42x = 130.45 × 78.71
  4. Step 4: Simplify right side
    87.42x = 10,267.85
  5. Step 5: Solve for x
    x = 10,267.85/87.42
  6. Step 6: Final answer
    x = 117.45

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.